Diorganodihalosilanes are hydrolyzed to produce a wide range of polyorganosiloxanes, which are sold into many different industries. Typically, diorganodihalosilanes are produced commercially by the Mueller-Rochow Direct Process, which comprises passing an organohalide, such as methyl chloride, over zero-valent silicon in the presence of a copper catalyst and various promoters. The Direct Process produces a mixture of organohalosilanes, the most valuable of which is dimethyldichlorosilane.
The zero-valent silicon used in the Direct Process is typically made by the carbothermic reduction of SiO2 in an electric arc furnace at extremely high temperatures. Generation of these extreme temperatures requires significant amounts of energy, which adds significant cost to the process of producing zero-valent silicon. Consequently, the use of zero-valent silicon also adds significant costs to the production of diorganodihalosilanes by the Direct Process.
Metal silicides, such as copper silicide, have been used in the direct process to promote the reaction of zero-valent silicon with organohalides to make diorganodihalosilanes. However, when used as a promoter, metal silicides are typically used at low levels with large amounts of zero-valent silicon and other catalysts and promoters.
Therefore, there is a need for more economical processes for producing diorganodihalosilanes that do not directly use zero-valent silicon produced by the carbotherminc reduction of SiO2.